​

function setup() {

    createCanvas(400, 400);

}

​

function draw() {

    //For (var BEGIN; END; INTERVAL){

    //DO SOMETHING }

    for (var x = 0; x < width; x += width / gridSize) {

        for (var y = 0; y < height; y += height / gridSize) {

            stroke(0);

            strokeWeight(1);

            ellipse(x + height / gridSize / 2, y + width / gridSize / 2, height / gridSize, width / gridSize);

        }

    }

}